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Someone Disconnects North Korea – Who?

North Korea went off the Internet Monday, 22 December 2014, at 16:15 UTC (01:15 UTC Tuesday in Pyongyang) after more than 24 hours of sustained weekend instability. Dyn continually measures the connectivity and performance of more than 510,000 individual networks worldwide, identifying impairments to Internet commerce. It’s a rare event these days when an entire country leaves the Internet (as Egypt did, or Syria). Even so, when North Korea’s four networks went dark, we were not entirely surprised, based on the fragility of their national connectivity to the global Internet.

Who caused this, and how? A long pattern of up-and-down connectivity, followed by a total outage, seems consistent with a fragile network under external attack. But it’s also consistent with more common causes, such as power problems. Point causes such as breaks in fiberoptic cables, or deliberate upstream provider disconnections, seem less likely because they don’t generate prolonged instability before a total failure. We can only guess. The data themselves don’t speak to motivations, or distinguish human factors from physical infrastructure problems.

As the sun rises in Pyongyang, the national Internet disconnection continues. An outage of this duration is not without precedent for North Korea. As we’ve written before, countries that have a very limited set of international connections are more likely than their better-connected counterparts to suffer from nation-scale disconnections, regardless of the cause.

In this case, North Korea has significantly less Internet to lose, compared to other countries with similar populations: Yemen (47 networks), Afghanistan (370 networks), or Taiwan (5,030 networks). And unlike these countries, North Korea maintains dependence on a single international provider, China Unicom. That’s a fragile state of affairs.

Update: All four North Korean prefixes have been restored to service at 01:46 UTC, after a national outage of nine and a half hours. Traffic is routing through China Unicom, just as before.